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arXiv · 1006.5546

Evidence of delocalized excitons in amorphous solids

Fabrizio Messina·Eleonora Vella·Marco Cannas·Roberto Boscaino
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Abstract

We studied the temperature dependence of the absorption coefficient of amorphous SiO$_2$ in the range from 8 to 17.5~eV obtained by Kramers-Kronig dispersion analysis of reflectivity spectra. We demonstrate the main excitonic resonance at 10.4~eV to feature a close Lorentzian shape red-shifting with increasing temperature. This provides a strong evidence of excitons being delocalized notwithstanding the structural disorder intrinsic to the amorphous system. Excitons turn out to be coupled to an average phonon mode of 83~meV energy.

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Fabrizio Messina, Eleonora Vella, Marco Cannas, Roberto Boscaino. 2010-06-29. Evidence of delocalized excitons in amorphous solids. https://doi.org/10.1103/physrevlett.105.116401

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